Semiconductor device

Abstract

A semiconductor device includes: a switching device including a main portion and a current sensing portion for detecting a current value of the main portion; a control IC including a gate drive unit that drives the switching device; a sensing resistor connected between an emitter of the main portion and an emitter of the current sensing portion and formed inside the control IC; a comparator comparing a sense voltage applied to the sensing resistor with a reference voltage; and a shut-down circuit shutting down an energization of the switching device when the sense voltage exceeds the reference voltage, wherein the sense voltage is more than or equal to 1 V when the energization of the switching device is shut down.

The invention claimed is: 
     
       1. A semiconductor device comprising:
 a switching device including a main portion and a current sensing portion for detecting a current value of the main portion; 
 a control IC including a gate drive unit that drives the switching device; 
 a sensing resistor connected between an emitter of the main portion and an emitter of the current sensing portion and formed inside the control IC; 
 a comparator comparing a sense voltage applied to the sensing resistor with a reference voltage; and 
 a shut-down circuit shutting down an energization of the switching device when the sense voltage exceeds the reference voltage, wherein 
 the sense voltage is more than or equal to 1 V when the energization of the switching device is shut down, 
 the gate drive unit includes a first gate drive unit driving the main portion, and a second gate drive unit driving the current sensing portion, and 
 an output voltage of the second gate drive unit is higher than an output voltage of the first gate drive unit. 
 
     
     
       2. The semiconductor device according to  claim 1 , wherein a current density of the current sensing portion is 120 to 420 A/cm 2 . 
     
     
       3. The semiconductor device according to  claim 1 , further comprising a gate resistor decreasing a gate voltage of the main portion. 
     
     
       4. The semiconductor device according to  claim 3 , wherein the gate resistor is incorporated in the switching device. 
     
     
       5. The semiconductor device according to  claim 3 , wherein the current sensing portion includes no gate resistor. 
     
     
       6. The semiconductor device according to  claim 1 , further comprising an amplifier amplifying a gate current of the main portion. 
     
     
       7. The semiconductor device according to  claim 1 , wherein a gate pad of the main portion is separated from a gate pad of the current sensing portion. 
     
     
       8. The semiconductor device according to  claim 1 , wherein the switching device is formed of a wide-band-gap semiconductor.